How does the body absorb food? How the food is absorbed

The digestion of food begins in the oral cavity, and the digestion of food in the oral cavity is mainly mechanical (food is ground), because the food stays in the oral cavity for a short time, so the digestion in the oral cavity does not play a big role.

After the food enters the stomach from the esophagus, it is subjected to the mechanical digestion of the gastric wall muscles and the chemical digestion of gastric juice, at this time, the protein in the food is initially decomposed by pepsin in the gastric juice (with the participation of gastric acid), and the gastric contents become a porridge-like chyme state, which is pushed to the duodenum through the pylorus many times in small quantities. After the chyme enters the duodenum from the stomach, it begins digestion in the small intestine.

The small intestine is the main site of digestion and absorption. Food is chemically digested in the small intestine by pancreatic juice, bile and intestinal fluid, as well as mechanical digestion by the small intestine, and various nutrients are gradually broken down into simple absorbable small molecules that are absorbed in the small intestine. As a result, after food passes through the small intestine, the digestion process is almost complete, leaving only the indigestible food residues, which enter the large intestine from the small intestine.

There is no digestion in the large intestine, and it only has a certain absorption function.

When the food you eat is chewed in the mouth, it is broken down, and it goes into the stomach to break down into molecules, and then it goes to the small intestine, and the velvet intestine of the small intestine absorbs the molecules, which is called sugar.

Then the rest goes to the large intestine, which absorbs water and then excludes

Digestive knowledge: 8 to 10 meters from the mouth to the end of the rectum. It takes 4 to 6 hours for food to empty in the stomach, and the diameter of the food is less than 2 mm to allow it to be expelled from the stomach.

Mechanical digestion and chemical digestion are carried out simultaneously. The food is mixed with three types of digestive saliva in the mouth, and bile and insulin are added to the duodenit.

The substances in food that can be absorbed and utilized by the body are called nutrients. Food contains six categories of nutrients: protein, starch, fat, vitamins, water and inorganic salts, each of which is necessary for the human body, fats, starches and proteins are macromolecular water-insoluble substances that cannot be directly absorbed by the wall of the digestive tract.

Only after being digested into small molecules such as glycerin, fatty acids, glucose and amino acids in the digestive tract can it be absorbed, glucose powder, vitamin tablets, and iodized salt are small molecule substances that can be directly absorbed by the body without digestion.

Food contains six categories of nutrients, which are indispensable elements for maintaining the material composition and physiological functions of living organisms, and are also the material basis for life activities.

It is now known that the human body contains 55% 61% water, 15% 18% protein, 10% 15% lipids, 3% 5% inorganic salts, and 1% 2% sugars. Proteins, lipids, sugars, etc. are very complex and large molecules, and there are many types of them, such as protein preparation, which is estimated to have more than 10 billion kinds of imitations, and there are 100,000 kinds of proteins in the human body.

Absorption of food.

Absorption is the process by which food is digested and becomes small molecules that pass through the mucous membranes of the digestive tract into the bloodstream and lymph. Vanish.

Chemistry and absorption are two complementary and closely related processes. Digestion is an important prerequisite for absorption, and absorption is the body's response.

An important guarantee for the utilization of nutrients. The ability and rate of absorption in different parts of the digestive tract depends on the parts of the digestive tract.

Tissue structure, as well as the extent to which food is digested in various parts and how long it stays. In the mouth and esophagus, food is almost none.

is absorbed; The stomach absorbs only a small amount of water and alcohol; Only the small intestine is the main site of absorption; Three major nutrients.

Most of the digestive products are absorbed in the duodenum and jejunum, and the ileum actively absorbs bile salts and vitamin B12. For large.

Some of the nutrients are usually absorbed by the time they reach the ileum, so when the contents of the small intestine enter the large intestine, they contain a very small amount of material that can be absorbed. The large intestine mainly absorbs water and salts.

Once nutrients have been digested and absorbed, they must be transported to tissues where they are needed or stored. Blood and lymph are the main carriers of absorbed nutrients. Most of the nutrients are absorbed into the blood circulation and then with the blood.

Protein molecules bind and are transported to various tissues and cells. Lipid digestion products are treated by the intestinal mucosa in the lymphatic capillary network-like group.

After tissue absorption, it enters the lymphatic fluid, which is transported through the lymphatic system and then enters the blood circulation.

Proteins and carbohydrates are broken down into amino acids and monosaccharides, respectively, in the mucosa of the small intestine in the digestive tract to take an active role.

It is absorbed by transport and enters the blood circulation for the body to use. Fats are digested into glycerol and fatty acids, which can be absorbed directly into the bloodstream, while most of the fatty acids enter the capillary lymphatic vessels and enter the blood circulation through the large lymphatic vessels. Fat-soluble vitamins are absorbed along with fatty acids.

Small nutrients present in food, such as water, vitamins and minerals, are directly absorbed in the small intestine. Water absorption is done by osmotic pressure, and water-soluble vitamins are diffusion.

Different minerals are absorbed in different ways.

It should be pointed out that there is an essential difference between dyspepsia and malabsorption. When there is a problem with the pancreas and liver, the secretion of digestive enzymes and digestive juices in the small intestine is affected, and indigestion symptoms will occur. And malabsorption is often caused by the intestines.

Caused by rapid peristalsis or abnormal function of the small intestine. Because indigestion and malabsorption occur in the small intestine, it is sometimes difficult to distinguish the two completely.

Do you want to know if the nutrients you eat are absorbed?

In fact, foods with high calcium content abound around us. Milk contains 100 120 mg of calcium per 100 grams of natural food, and about 240 280 mg of calcium per bag of commercially available milk, and is easily absorbed by the human body, making it the most ideal source of calcium. If a child drinks 250 milliliters of milk and a cup of yogurt a day, he can supplement 400 500 milligrams of calcium, supplemented with calcium-rich vegetables, soy products, etc., which can basically meet the calcium needs.

Beans, fish and shrimp, dried fruits such as hazelnuts and peanuts, kelp, fungus, shiitake mushrooms, sesame sauce and many green vegetables are good for calcium**. Tofu adds some electrolytes in the process of marinating to precipitate the protein, such as gypsum in southern tofu, that is, calcium sulfate, and northern tofu in brine, which is magnesium-containing salt, which is also beneficial to calcium supplementation.

In the daily cooking process, attention should also be paid to reducing the loss of calcium. If food should be stored safely; Do not stir when heating the milk to avoid the loss of calcium; Vegetables should be washed before cutting, should not be cut too much, stir-fry should add more water, cooking time should not be too long; Vegetables containing more oxalic acid, such as spinach, should be blanched with hot water to dissolve oxalic acid.

What is the digestion process like? It first passes through the mouth, then through the stomach, and finally through the large intestine and small intestine, and finally it is excreted as food residue.